Natural History of Isolated Deep Vein Thrombosis of the Calf (CALTHRO)

Tracking Information
First Submitted Date	January 2, 2009
First Posted Date	January 5, 2009
Last Update Posted Date	September 18, 2009
Study Start Date	September 2005
Actual Primary Completion Date	September 2009 (Final data collection date for primary outcome measure)
Current Primary Outcome Measures; (submitted: January 2, 2009)	Thrombotic complications (deep vein thrombosis and/or pulmonary embolism within three months from first examination [ Time Frame: three months from first examination ]
Original Primary Outcome Measures	Same as current
Change History	Complete list of historical versions of study NCT00816920 on ClinicalTrials.gov Archive Site
Current Secondary Outcome Measures; (submitted: January 2, 2009)	other vascular complications; how many isolated distal DVT will be diagnosed [ Time Frame: three months from first examination ]
Original Secondary Outcome Measures	Same as current
Current Other Outcome Measures	Not Provided
Original Other Outcome Measures	Not Provided
Descriptive Information
Brief Title	Natural History of Isolated Deep Vein Thrombosis of the Calf
Official Title	Diagnosis and Evolution of Isolated Deep Vein Thrombosis of the Calf in Symptomatic Outpatients. The Blind, Prospective "CALTHRO" Study.
Brief Summary	Whether isolated distal DVT (IDDVT), DVT confined to the calf, should be looked for and diagnosed to allow them to be treated with anticoagulants remains one of the still unsolved issues in vascular medicine, especially because of the insufficient data on clinical risks of untreated distal DVT. Management studies have shown that it is safe to withhold anticoagulation in outpatients with suspected DVT if compression ultrasonography (CUS) limited to the proximal deep veins yields normal results on presentation and on repeated examination after 5 to 7 days. This strategy is based on the premise that IDDVT do not need to be diagnosed and treated, what is necessary when they extend involving the proximal veins. There is no general agreement, however, on the assumption that the non-extending IDDVT do not need to be diagnosed and treated, and many authors recommend to perform a single CUS examination extended to the distal deep veins. All the available studies have treated with anticoagulants the diagnosed IDDVT and no adequate information is available on the risk of IDDVT left untreated. The present study, performed in outpatients with suspected leg DVT, aims at assessing the clinical consequences of IDDVT diagnosed (by a complete US investigation) but not treated because the results of this investigation remain blind to both the patient and the treating doctor, whereas the diagnostic-therapeutic procedure remains the usual one, based on CUS investigation limited to diagnose proximal DVT, to be repeated after 5-7 days (or earlier) to exclude an extension to proximal veins of an IDDVT potentially present.
Detailed Description	Outpatients symptomatic for suspected DVT of a leg are examined by a vascular doctor according to standard procedure based on pre-test clinical probability (PTCP) assessment, D-dimer assay and a CUS limited to the proximal deep veins. Those in whom a proximal DVT is excluded and have intermediate/high PTCP or altered D-dimer level are eligible for the study. The included patients are immediately submitted to an extensive echo-color-Doppler examination of calf deep veins by a different vascular doctor and results are closed in an envelope that will be open after three months (or before if necessary). In the meantime, patients will follow the standard diagnostic procedure: they receive an appointment to come back in 5-7 days for a further CUS examination, or even before in case of worsening of symptoms/signs. All the included patients receive a telephone call after three months to exclude possible complications.
Study Type	Observational
Study Design	Observational Model: Cohort; Time Perspective: Prospective
Target Follow-Up Duration	Not Provided
Biospecimen	Not Provided
Sampling Method	Non-Probability Sample
Study Population	outpatients with suspected deep vein thrombosis (DVT) of a leg in whom a proximal DVT is excluded. The study is not funded. As a result, it will not be possible to enroll all consecutive eligible patients; rather patients will be included based on the availability of expert medical staff in the day of their presentation (in general the first patient of the day).
Condition	Isolated Distal DVT; Proximal DVT; Pulmonary Embolism
Intervention	Other: Ultrasound examination of leg veins; Outpatients symptomatic for leg DVT follow the standard diagnostic procedure (ultrasound examination of proximal deep veins, pre-test clinical probability and D-dimer, and a second US after 5-7 days) to exclude proximal DVT; they also receive by another doctor a complete US examination of the deep leg veins to assess the presence of isolated calf DVT, the results of the latter examination are kept blind to the patient and to the treating doctor, and disclosed after three months
Study Groups/Cohorts	1; Outpatients with suspected leg DVT after exclusion of proximal DVT; Intervention: Other: Ultrasound examination of leg veins
Publications *	Not Provided
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
Recruitment Information
Recruitment Status	Completed
Estimated Enrollment; (submitted: January 2, 2009)	500
Original Estimated Enrollment	Same as current
Actual Study Completion Date	September 2009
Actual Primary Completion Date	September 2009 (Final data collection date for primary outcome measure)
Eligibility Criteria	Inclusion Criteria: suspected deep vein thrombosis of a leg; intermediate/high pre-test clinical probability or high D-dimer levels Exclusion Criteria: age < 18 years; presence of proximal DVT; suspected isolated iliac DVT; symptoms/signs lasting from > 30 days; presence of symptoms of pulmonary embolism; pregnancy or puerperium; full dose treatment with heparin or derivatives from > 1 day; presence of superficial vein thrombosis; limited life expectancy (< 6 months); geographically inaccessible location; inability or refusal to give consent; participation in other clinical studies
Sex/Gender	Sexes Eligible for Study: All
Ages	18 Years and older (Adult, Senior)
Accepts Healthy Volunteers	No
Contacts	Contact information is only displayed when the study is recruiting subjects
Listed Location Countries	Italy
Removed Location Countries
Administrative Information
NCT Number	NCT00816920
Other Study ID Numbers	24/2001/O EM60/2007/O
Has Data Monitoring Committee	Yes
U.S. FDA-regulated Product	Not Provided
IPD Sharing Statement	Not Provided
Responsible Party	Gualtiero Palareti, Azienda Ospedaliero-Universitaria di Bologna, Policlinico S. Orsola-Malpighi
Study Sponsor	St. Orsola Hospital
Collaborators	Not Provided
Investigators	Principal Investigator: Gualtiero Palareti, MD Azienda Ospedaliero-Universitaria di Bologna, Policlinico S. Orsola-Malpighi
PRS Account	St. Orsola Hospital
Verification Date	September 2009